Fire Safety Laws Fit for Purpose ?

Is a re-think of fire safety regulations required, because some business owners appear to continually flout the rules

Looking at the continuing stream of prosecutions, you get the distinct impression that a large proportion of the business sector just doesn't get fire safety. Regularly, those people we see in the courts are small operators in high-risk sectors: hotel owners, operators of guest houses, and landlords. Then of course there's the retail sector also routinely in the dock -- an industry in which individual managers take a large share of responsibility for standards at their own stores.

What these have in common is that the level of risk from fire is high -- either due to the presence of sleeping accommodation and/or the presence of the public. As any fire risk assessor will tell you, the prosecutions are the tip of the iceberg. There's plenty of evidence that a high proportion of businesses operate with very poor fire safety standards.

What's the issue?

There seem to be a number of factors at play:

• low likelihood of a fire;
• low likelihood of a prosecution; and
• low likelihood of an inspection.

It's always hard to persuade people to spend money, time, and effort to solve a problem they don't think they have. Since the resources of fire and rescue services have been diverted to domestic accommodations for higher risk residents, it seems there's less chance than ever of getting caught out for low standards.

Add to all that the difficulty duty holders have in understanding exactly what's needed to fulfil their legal obligations, plus the costs, plus the time or effort to carry out routine testing to ensure that routes are always unobstructed, etc.

If you take the carrot and stick analogy then there's not much of either.

Fire certificates

It was a totally different approach whereby certain types of premises with particular levels of occupancy had to apply for one. You were told exactly what had to be done, right down to the content of annual staff training. If you wanted to do things differently, you were supposed to notify the authority. Contravening a fire certificate could make you end up in prison.

Did it work? Well not exactly. People made changes and forgot to tell the fire brigade. And the authorities didn't have the time to do much revisiting and checking of the premises. Then, of course, as not all premises had to have a certificate. The Fire Precautions (Workplace) Regulations 1997 came in (since repealed), and as a result risk assessments were supposed to be carried out, but mostly were not.

But the part which was good about the old system was the clarity about what had to be done, something which is now sorely lacking.

A myriad of small businesses have now grasped the risk -assessment message, i.e., that they can decide for themselves. They've decided to do nothing. Or maybe they've bought a fire extinguisher but not much else.

The fire and rescue services were already fighting an uphill struggle to get these businesses sorted out, when along came a recession. Go in heavy and the smaller hotel, guest house, etc. will fold with the consequential job losses and political backlash.

And to underline the point the government is now tying regulators in to a commitment to be business friendly.

Safety and health advice days

It's a capital market place, so ideally natural pressures would lead to higher standards. For example, if there's a good supply of high-quality safe accommodation at affordable prices, the cowboy landlords would lose out in the Houses in Multiple Occupation market. Not really a likely scenario for the next couple of decades, though, I'd suggest.Could we nudge people in the right direction instead, with stories of fire victims or increasing the knowledge of managers in the higher risk sectors with free seminars?

One trick the HSE uses to good effect is SHAD events (Safety and Health Advice Days). The deal is that if you turn up for free training, you're unlikely to be inspected. Could there be scope for something similar in the fire sector?

What else could we try?

1. Increase the penalties: even with a low possibility of prosecution, if the penalties were severe fewer would be tempted.
2. Increase personal liability: people generally hate personal liability, they prefer to hide behind a company. If it was more likely you'd get a personal fine, community-service order or jail sentence, then as a manager maybe you'd make better fire safety decisions.
3. Increase the number of prosecutions: When word spreads locally that so-and-so got shut down for fire safety offences, others start to take note.
4. Increase the numbers of inspections: I'm guessing this is out of the question in the current climate?
5. Change the law to make the requirements more rigid.
6. Remove regionalisation and provide one central fire information source for the UK.

Perhaps the answer is a touch of all of the above. But one thing which is within our grasp is to simply make it much easier for people to know what to do. We need to return to a clear message: a means of escape, fire fighting measures, a means of raising the alarm, and maintenance.

smoke alarms be replaced after 10 years

Smoke Alarms be Replaced After 10 years.

In 1992, the Building Regulations were amended requiring every new build to allow for mains-wired, interconnected smoke alarms to be installed. With many alarms installed under this Regulation still in use and potentially approaching their twentieth year, it was necessary to research a recommendation as to when mains powered smoke alarms should be replaced.

Current recommendations

1.     The majority of research found on this subject emanates from the US. The US National Fire Protection Association (NFPA) have issued NFPA Standard 72, National Fire Alarm and Signalling Code (2010 edition), which states:

1.     "Replace all smoke alarms, including those that use ten-year batteries and hard-wired alarms, when they are ten years old or sooner if they don’t respond properly when tested."

2.     US fire safety websites, along with those in the UK, Canada, New Zealand and Australia, tend to recommend the replacement of domestic smoke alarms, whether battery or mains-wired, when they:

o    Fail to respond to tests

o    Are ten years old (varying between date of installation and manufacture)

Why Replace Alarms?

Several reasons are provided to justify the replacement of smoke alarms after ten years.

3.     The Minnesota Department of Public Safety cite a nationwide study undertaken by the Consumer Product Safety Commission (CPSC), which states that 97% of smoke alarms should still be functioning after one year, if supplied with power. After ten years it is 73%, whereas after 20 years, this figure stands at 54%. The study also indicated that 60% of the failures were due to flat or removed batteries or a disconnected power supply and the study offered possible reasons for this. Ageing alarms may experience sensitivity drifting, which may, in turn, result in an increased frequency of accidental activation and an increase in people removing the power supply. It was thought that newer alarms with a ‘hush’ feature may contribute to remedying this

4.     An NFPA report cites a study undertaken by Canada’s Ontario Housing Corporation supporting the fact that 3% of smoke alarms will fail within one year. They also say that after 30 years, nearly all the alarms will have failed. They conclude that replacement after ten years, with roughly a 30% probability of failure, is an appropriate balance between safety and cost

5.     The South Australian Metropolitan Fire Service state that smoke alarm technology has improved significantly since legislation was introduced (similar requirements to the 1992 UK ones were introduced in Australia in 1995) and replacing old smoke alarms is an ideal opportunity to upgrade smoke alarm systems. The Australian Standard for smoke alarms (AS 3786) specifies an effective life of 10 years, suggesting that after that time effectiveness may be compromised with accumulated dust, insects, airborne contaminants and corrosion of electrical circuitry

6.     In the early 1990s, the US Consumer Product Safety Commission undertook an extensive study, called the National Smoke Detector Project, to examine smoke alarm ownership and operability. Some failures were found in smoke alarms, but there were no large or systematic problems identified with detector designs or manufacturing practices that cast any doubt on their long term reliability. However, a variety of component failures, corroded battery clips and deterioration and corrosion of the horn element contacts were found in a few smoke alarms

7.     Other reports from New Zealand and Canada looked at operability of battery smoke alarms, but no further reports on the operability and longevity of mains-wired smoke alarms could be found

Testing Smoke Alarms

8.     It should be noted that the regular testing of smoke alarms should help identify inoperability as testing a smoke alarm simulates smoke and does not simply test the power supply. This would indicate smoke alarm maintenance messages remain a priority. However, it was queried whether all smoke alarm test functions operate in this way, or whether some simply do test power supply, be it battery or mains-wired

9.     The general view from UK based smoke alarm manufacturers reflects the findings elsewhere. With contaminants such as dust, insects, grease and nicotine, the smoke alarm chamber is susceptible to becoming excessively sensitive or insensitive. This may lead to either an increase in nuisance false alarms, or to eventually becoming unable to detect smoke. One manufacturer reports that contamination is extremely variable, but that field experience indicated that 10 years is a reasonable compromise

Conclusion

10.  Evidence of smoke alarm longevity appears to be scarce and inconclusive. As with other electronic items, there will be failures in the units when they are produced and failures during their lifetime due to individual component faults. Similarly, as they get older more faults are likely to occur. Problems specific to smoke detectors include increased sensitivity

11.  In all the work identified so far, none has specifically concentrated on the failure of smoke alarms when they age. Smoke alarms do fail but the rate at which they do has not been accurately determined or related to their age.

12.  Despite there not being much research, it does seem appropriate to replace smoke alarms after ten years (in line with manufacturers advice), unless individual alarm testing suggests earlier replacement.

Mains-wired interconnected alarms – Replacement kits

13.  Safelincs has developed products designed to help facilitate the process of replacing the smoke detector heads for mains-wired interconnected smoke alarms

Disposal of old Smoke Alarms

Smoke and heat alarms fall under the WEEE (Waste Electrical and Electronic Equipment) regulations. Under the regulations retailers pay a fee to allow their customers to take old smoke and heat alarm to their local recycling centre (Distributor Take-Back Scheme). To find you local recycling centre visit the recycle-more bank locator.

Domestic Customers

Ideally old smoke and heat alarms should be taken to local recycling centres for disposal. However small numbers of alarms can be disposed of along with normal household refuse, a common misunderstanding is that the crossed-out wheelie bin on the back of the alarm means that they must not be placed in a normal waste bin. This symbol actually just means that the alarm falls under the WEEE regulations.

Business Customers

Business customers cannot dispose of smoke alarms along with their normal refuse and should instead take them to their local recycling centre.

Customer Purchasing from Safelincs

Customers that purchased their alarms from Safelincs originally or that are purchasing new alarms from us now can send their old alarms back to us for disposal.

Emergency Lighting under BS 5266

BS 5266: Emergency Lighting

BS 5266-2:1998 - Code of practice for electrical low mounted way guidance systems for emergency use.

BS 5266-4:1999 - Code of practice for design, installation, maintenance and use of optical fibre systems.

BS 5266-5:1999 - Specification for component parts of optical fiber systems.

BS 5266-6:1999 - Code of practice for non-electrical low mounted way guidance systems for emergency use. Photoluminescent systems.

BS EN 1838:1999 - Lighting applications. Emergency lighting.

BS EN 50172:2004 - Emergency escape lighting systems.

BS 5266-1:2011 - Code of practice for the emergency escape lighting of premises.

Fire Alarm System Classifications under BS5839

BS5839 Fire Alarm System Classifications

The British Standard splits fire alarm system designs into different classifications of system.  This article looks at the different types of fire alarm system classifications for Public, Commercial and Industrial buildings (a further article will be written to explain domestic system classifications).

BS5839 Splits fire alarm systems into 3 categories.  These 3 categories are Category P Systems, Category L Systems and Category M Systems.  Please find following a description of these categories.

All the systems described below are expected to have manual call points on all final exits, entrances to stairwells and corridors where persons are not expected to walk more than 45 metres to operate a call point.

Category P Fire Alarm Systems

BS5839 Category P Fire Alarm Systems are designed specifically for protection of property only.  Category P systems are split into 2 classifications P1 or P2.

The main objective of a Category P1 fire alarm system is to provide the earliest possible warning of a fire to minimise the time between ignition and the arrival of the fire fighters. 

The difference between a P1 and a P2 system is that a P1 system is designed to protect the whole building, whereas a P2 system is installed in defined parts of the building only.  These defined parts of the building may be areas with an extraordinary high fire risk or hazard.

BS5839 Category P Fire Alarm System Equipment

To create a category P fire alarm system it is possible to use either conventional, analogue addressable or wirelesss fire alarm system equipment.  We have an extensive range of all these types of systems available. 

For smaller installations a conventional / non-addressable fire alarm system may be more cost effective, whereas for larger installations an analogue addressable system would be more suitable.

In buildings where installations are difficult wireless fire alarm system equipment can lead to cost savings.  These systems can also be used for category P systems.

Category L Fire Alarm Systems

The main objective BS5839 Category L Fire Alarm System is life protection.  These systems are split into 5 classifications L1, L2, L3, L4 and L5.

BS5839 Classification L1 Explanation

A BS5839 L1 classification includes automatic fire detection in all rooms, on all escape routes and in all voids over 800mm in height.  Sounders positioned throughout the building to achieve a minimum of 65dB(A) throughout the building and 75dB(A) at bedhead where there is a sleeping risk.  In areas of high ambient noise sound levels the fire alarm sound levels should be 5dB(A) above the normal noise level although not exceeding 120dB(A).

BS5839 Classification L2 Explanation

A BS5839 Classification L2 System should include automatic fire detection on all escape routes and rooms leading onto escape routes.  An L2 system can also include additional areas deemed as a high risk not included in the escape routes and adjoining rooms, such as boiler houses.  The sounders in the building should be according to the description in the BS5839 Category L1 description as above.

BS5839 Classification L3 System Explanation

A BS5839 Classification L3 system is very similar to a category L2 system in that automatic fire detection should be positioned on escape routes and adjoining rooms, although it does not have to include for additional areas deemed to have a high fire risk.  The sounders in the building should be according to the description in the BS5839 Category L1 description as above.

BS5839 Classification L4 System Explanation

A BS5839 Classification L4 system includes automatic fire detection on escape routes only, and not in the adjoining rooms as per the L2 and L3 classifications.  The sounders in the building should be according to the description in the BS5839 Category L1 description as above.

BS5839 Classification L5 System Explanation

A BS5839 Classification L5 System is designed for buildings that have a particular fire risk identified which warrants some special attention.  For example if there is an area of high fire risk which is considered worthy of having some automatic detection but a manual system is also needed, then this will be termed as L5/M.  The sounders in the building should be according to the description in the BS5839 Category L1 description as above.

Category M Fire Alarm Systems

A BS5839 Category M Fire Alarm System is a manual operation only system which has call points on all exits as well as corridors where persons are not expected to walk any more than 45m to operate one.

Category L Fire Alarm System Equipment Available At The Safety Centre

Have you been informed that you require a BS5839 Category L Fire Alarm System?  If so, The Safety Centre has hundreds of products available suitable for creating BS5839 Category L Fire Alarm Systems.  We have products available to suit all budgets.  We have extensive ranges of equipment from many of the worlds leading fire alarm system manufacturers.  These ranges include fire alarm panels, detectors, manual call points, sounders and beacons all suitable for use on BS5839 Category L fire alarm systems.

BS5839 Part 6 2004 - Fire Alarm System Installations in Dwellings

BS5839 Part 6 2004 - Fire Alarm System Installations in Dwellings

The British Standard Associated with Fire Alarm System Installations in Dwellings is BS5839 Part 6 2004.  This part of the British Standard is split up into 3 categories of systems.  These categories are as follows:-

• LD1 - Alarms in all circulation spaces that form part of escape routes and all areas where a fire might start, but not bathrooms, shower rooms or toilets
• LD2 - Alarms in all circulation spaces that form part of escape routes and rooms or areas that present a high fire risk
• LD3 - Alarms in circulation spaces that form part of escape routes

The category of system that should be installed in a building is often defined by Councils, Insurance Companies, Fire Officers, Building Control and many others.

The above categories indicate the category of system that should be installed.  Further to this information different grades of system may be specified.  

These are as follows:-

• Grade A - A full system with control and indicating equipment installed to BS 5839: Part 1
• Grade B - Detectors and sounders using simpler specified equipment
• Grade C - Detectors and sounders or alarms with central control
• Grade D - Mains powered alarms with an integral stand-by power supply
• Grade E - Mains powered alarms with no stand-by power supply
• Grade F - Battery powered alarms

These grades are used in conjunction with the category type, to indicate what type of system should be installed within the property.  For example if an LD2 Grade A system is requested, this would require a system with alarms in circulation areas that form escape routes and high fire risk areas with the equipment with control and indicating equipment compliant to BS5839 Part 1.

Beam Detectors Installation process

Beam Detectors are a well-established product available in the fire alarm industry.  Commonly beam detectors are used to provide automatic fire detection in large open spaces, such as warehouses, airports and factories.

A beam detector works by having a transmitter and receiver.  The transmitter part of the beam detector fires out an infrared beam which is then received by the receiver.  The beam detector is designed to set a fire alarm system into alarm when a pre-set level of smoke obscures the infrared beam.  Beam detectors are available in two types, these are reflective beam detectors and point to point type beam detectors.  A reflective beam detector works by firing the infrared beam from a transmitter at a reflector positioned at the other end of the area being covered by the beam detector, the beam is then reflected back towards the beam detector unit which also has a receiver built into the enclosure.  A point to point beam detector operates by having a dedicated transmitter located at one side of the area being covered by the beam detector and then having a dedicated receiver at the other end of the protected area.

One major advantage of beam detectors is that they can be located a much greater heights than standard point detectors.  The maximum mointing height of a point detector is 10.5 metres where as BS5839 recommends that beam detectors can be mounted up to a height of 25 metres.  Another advantage of a beam detector is that one beam detector can provide automatic fire detection for an area which would require several standard point detectors, which means that using beam detectors can be much more cost effective than using standard point detectors.

The Siting of Beam Detectors

• Beam Detectors can be used at heights of up to 25 metres
• For apex ceilings extended coverage can be achieved by 1% for each degree of angle
• Beam Detectors should be positioned within 600mm of the highest point of the ceiling
• Ceiling beams close to walls (500mm) or temporary obstructions should be avoided
• Transmitters & Receivers should be mounted on solid surfaces which are not effected by wind or natural temperature changes
• Additional units may be included in atria to detect at lower levels, to counter statification effect.

Bonding, Grounding and Earthing

Bonding, Grounding and Earthing

In Fire detection system or CCTV / Access Control System this 3 terms are very important during doing the errection, testing & commissioning activity.

• Bonding is more clear word compare to Grounding and Earthing but there is a micro difference between Grounding and Earhing.
• Earthing and Grounding are actually different terms for expressing the same concept. Ground or earth in a mains electrical wiring system is a conductor that provides a low impedance path to the earth to prevent hazardous voltages from appearing on equipment. Earthing is more commonly used in Britain, European and most of the commonwealth countries standards (IEC, IS), while Grounding is the word used in North American standards (NEC, IEEE, ANSI, UL).
•  We understand that Earthing and Grounding are necessary. We need to understand that there are really two separate things we are doing for same purpose that we call Grounding or Earthing.
• The Earthing is to reference our electrical source to earth (usually via connection to some kind of rod driven into the earth or some other metal that has direct contact with the earth).
• The grounded circuits of machines need to have an effective return path from the machines to the power source in order to function properly (Here by Neutral Circuit).
•  In addition, non-current-carrying metallic components in a System, such as equipment cabinets, enclosures, and structural steel, need to be electrically interconnected and earthed properly so voltage potential cannot exist between them. However, troubles can arise when terms like “bonding,” “grounding,” and “earthing” are interchanged or confused in certain situations.
• In TN Type Power Distribution System, in US NEC (and possibly other) usage: Equipment is earthed to pass fault Current and to trip the protective device without electrifying the device enclosure. Neutral is the current return path for phase. These Earthing conductor and Neutral conductor are connected together and earthed at the distribution panel and also at the street, but the intent is that no current flow on earthed ground, except during momentary fault conditions. Here we may say that Earthing and grounding are nearly same by practice.
• But In the TT Type Power Distribution System (In India) Neutral is only earthed (here it is actually called Grounding) at distribution source (at distribution transformer) and Four wires (Neutral and Three Phase) are distributed to consumer. While at consumer side all electrical equipments body are connected and earthed at consumer premises (here it is called Earthing). Consumer has no any permission to mix Neutral with earth at his premises here Earthing and grounding is the different by practice.

But in both above case Earthing and Grounding are used for the same Purpose. Let’s try to understand this terminology one by one.

Bonding:

§  Bonding is simply the act of joining two electrical conductors together. These may be two wires, a wire and a pipe, or these may be two Equipment’s.

§   Bonding has to be done by connecting of all the metal parts that are not supposed to be carrying current during normal operations to bringing them to the same electrical potential.

§  Bonding ensures that these two things which are bonded will be at the same electrical potential. That means we would not get electricity building up in one equipment or between two different equipment. No current flow can take place between two bonded bodies because they have the same potential.

§  Bonding, itself, does not protect anything. However, if one of those boxes is earthed there can be no electrical energy build-up. If the grounded box is bonded to the other box, the other box is also at zero electrical potential.

§  It protects equipment & Person by reducing current flow between pieces of equipment at different potentials.

§  The primary reason for bonding is personnel safety, so someone touching two pieces of equipment at the same time does not receive a shock by becoming the path of equalization if they happen to be at different potentials.

§  The Second reason has to do with what happens if Phase conductor may be touched an external metal part. The bonding helps to create a low impedance path back to the source. This will force a large current to flow, which in turn will cause the breaker to trip. In other words, bonding is there to allow a breaker to trip and thereby to terminate a fault.

§  Bonding to electrical earth is used extensively to ensure that all conductors (person, surface and product) are at the same electrical potential.  When all conductors are at the same potential no discharge can occur.  

Earthing:

§  Earthing means connecting the dead part (it means the part which does not carries current under normal condition) to the earth for example electrical equipment’s frames, enclosures, supports etc.

§  The purpose of earthing is to minimize risk of receiving an electric shock if touching metal parts when a fault is present. Generally green wire is used for this as a nomenclature.

§  Under fault conditions the non-current carrying metal parts of an electrical installation such as frames, enclosures, supports, fencing etc. may attain high potential with respect to ground so that any person or stray animal touching these or approaching these will be subjected to potential difference which may result in the flow of a current through the body of the person or the animal of such a value as may prove fatal.

§  To avoid this non-current carrying metal parts of the electrical system are connected to the general mass of earth by means of an earthing system comprising of earth conductors to conduct the fault currents safely to the ground.

§  Earthing has been accomplished through bonding of a metallic system to earth. It is normally achieved by inserting ground rods or other electrodes deep inside earth.

§  Earthing is to ensure safety or Protection of electrical equipment and Human by discharging the electrical energy to the earth.

Grounding:

§  Grounding means connecting the live part (it means the part which carries current under normal condition) to the earth for example neutral of power transformer.

§  Grounding is done for the protections of power system equipment and to provide an effective return path from the machine to the power source. For example grounding of neutral point of a star connected transformer.

§  Grounding refers the current carrying part of the system such as neutral (of the transformer or generator).

§  Because of lightening, line surges or unintentional contact with other high voltage lines, dangerously high voltages can develop in the electrical distribution system wires. Grounding provides a safe, alternate path around the electrical system of your house thus minimizing damage from such occurrences.

§  Generally Black wire is used for this as a nomenclature.

§  All electrical/electronic circuits (AC & DC) need a reference potential (zero volts) which is called ground in order to make possible the current flow from generator to load. Ground is May or May not be earthed. In Electrical Power distribution it is either earthed at distribution Point or at Consumer end but it is not earthed in Automobile( for instance all vehicles’ electrical circuits have ground connected to the chassis and metallic body that are insulated from earth through tires). There may exist a neutral to ground voltage due to voltage drop in the wiring, thus neutral does not necessarily have to be at ground potential.

§  In a properly balanced system, the phase currents balance each other, so that the total neutral current is also zero. For individual systems, this is not completely possible, but we strive to come close in aggregate. This balancing allows maximum efficiency of the distribution transformer’s secondary winding

Difference between Earthing & Grounding:

There is no major difference between earthing and Grounding, both means “Connecting an electrical circuit or device to the Earth”. This serves various purposes like to drain away unwanted currents, to provide a reference voltage for circuits needing one, to lead lightning away from delicate equipment. Even though there is a micro difference between grounding & earthing.

(1) Difference in Terminology:

§  In USA term Grounding is used but in UK term Earthing is used.

(2) Balancing the Load Vs Safety:

§  Ground is a source for unwanted currents and also as a return path for main current some times. While earthing is done not for return path but only for protection of delicate equipment’s. It is an alternate low resistance path for current.

§  When we take out the neutral for a three phase unbalanced connection and send it to ground, it is called grounding. Grounding is done to balance unbalanced load. While earthing is used between the equipment and earth pit so as to avoid electrical shock and equipment damage.

(3) Equipment Protection Vs Human Safety:

§  Earthing is to protect the circuit elements whenever high voltage is passed by thunders or by any other sources while Grounding is the common point in the circuit to maintain the voltage levels.

§  Earth is used for the safety of the human body in fault conditions while Grounding (As neutral earth) is used for the protection of equipment’s.

§  Earthing is a preventive measure while Grounding is just a return path

§  The ground conductor provides a return path for fault current when a phase conductor accidentally comes in contact with a grounded object. This is a safety feature of the wiring system and we would never expect to see grounding conductor current flow during normal operation.

§  Do not Ground the Neutral Second time When It is grounded either at Distribution Transformer or at Main service Panel of Consumer end.

§  Grounding act as neutral. But neutral cannot act as ground.

(4) System Zero Potential Vs Circuit Zero Potential:

§  Earthing and Grounding both is refer to zero potential  but the system connected to zero potential is differ than Equipment connected to zero potential .If a neutral point of a generator or transformer is connected to zero potential then it is known as grounding. At the same time if the body of the transformer or generator is connected to zero potential then it is known as earthing.

§  The term “Earthing means that the circuit is physically connected to the ground and it is Zero Volt Potential to the Ground (Earth) but in case of “Grounding” the circuit is not physically connected to ground, but its potential is zero(where the currents are algebraically zero) with respect to other point, which is also known as “Virtual Grounding.”

§  Earth having zero potential whereas neutral may have some potential. That means neutral does not always have zero potential with respect to ground. In earthing we have Zero Volt potential references to the earth while in grounding we have local Zero Volt potential reference to circuit. When we connect two different Power circuits in power distribution system, we want to have the same Zero Volt reference so we connect them and grounds together. This common reference might be different from the earth potential.

Illegal Practice of interchange Purpose of Grounding & Earthing wire

§  Neutral wire in grid connections is mandatory for safety. Imagine a person from 4th floor in a building uses Earth wire (which is earthed in the basement at Basement) as neutral to power his lights. Another Person from 2nd floor has a normal setup and uses neutral for the same purpose. Neutral wire is also earthed at the ground level (as per USA practice Neutral is Grounded (earthed) at Building and as per Indian Practice it is Grounded (earthed) at Distribution Transformer). However, ground wire (Neutral wire) has a much lower electrical resistance than Earth Wire (Earthing) which results in a difference of electrical potential (i.e. voltage) between them. This voltage is quite a hazard for anyone touching a Earth wire (Metal Body of Equipment) as it may have several tens of volts.

§  The second issue is legality. Using ground wire instead of neutral makes you an energy thief as the meter uses only the Phase and neutral for recording your energy consumption. Many Consumers make energy theft by using Earthing wire as a Neutral wire in an Energy meter.

How to Apply to Fire Safety Systems and Installations

The NFPA 70, or NEC, sets the foundation for electrical safety in residential, commercial, and industrial occupancies in the United States. Updated every three years, it's a living document that evolves alongside the ever-advancing field of electrical technology. Let's go through a fast summary of NFPA 70 (also expressed as NFPA70 and NFPA-70). This will allow you, as a fire safety professional, to navigate and use its provisions more effectively.

Application of NEC to Electrical installation Directly

The NEC is divided into 9 chapters, with each chapter further divided into parts, articles, and sections. The chapters cover specific aspects of electrical installations, ranging from wiring methods, equipment for general use, special occupancies, special equipment, to special conditions.

·        Article 210: This covers branch circuits, the smallest units of an electrical system that directly supply power to electrical equipment. It includes standards for circuit ratings, protection, and load calculations.

• Article 215: It focuses on feeder circuits, which transport electricity from service equipment to branch circuits. Understanding this section is essential for ensuring proper feeder size and load.
• Article 230: This provides guidelines for service installations, the point where a building or system receives power from the utility source. It covers service conductors, equipment, and overcurrent protection.
• Article 240: Overcurrent protection is a crucial safety element of any electrical system. This section provides guidance for the selection and installation of overcurrent protective devices.
• Article 250: This focuses on grounding and bonding, two critical aspects of electrical safety. It defines how to properly ground electrical systems and equipment, ensuring safety and reducing the risk of electrical shock and fires. Digitize equipment is thoroughly grounded to protect itself from surge damage, and this obviously depends on the earth ground available in the building.
• Article 760: This section is of particular interest to you, as it pertains specifically to fire alarm systems. NEC Article 760 covers fire alarm system power sources, circuit identification, installation, and more.

Application of NFPA 70 to Fire Alarm Installations Directly

One of the most direct overlaps between the NEC and fire safety is found in NFPA 70 Article 760, "Fire Alarm Systems," within the NEC. This article deals specifically with the installation of wiring for fire alarm systems.

NFPA 70 Article 760 outlines the specific wiring methods for both non-power-limited and power-limited fire alarm circuits. This distinction is critical as power-limited circuits are designed to limit electrical energy to a level that does not ignite a fire in normal or fault conditions. Non-power-limited circuits, on the other hand, may have enough energy to ignite a fire. That's why they require more robust safety measures.

Power-limited fire alarm circuits are generally easier to install due to fewer restrictions, as they don't pose as much of a fire hazard. They can often be installed using similar techniques to those used for regular low-voltage wiring.

Non-power-limited circuits, however, must adhere to stricter standards. They need to be installed in such a way that reduces the potential for faults and ensures a higher degree of safety. Specific types of cable or conduit may be required, and separation from other electrical cables may be mandated.

Additionally, the NEC dictates how fire alarm circuits should be protected from accidental damage or disconnection. The use of dedicated circuit breakers or disconnecting means, identifiable and accessible control equipment, and appropriately labeled circuits are all examples of NEC provisions related to fire alarm installations.

Other Overlaps between Fire Safety and NFPA 70

Beyond fire alarm systems, several other aspects of the NEC directly influence fire safety. For example:

• Grounding (Article 250): Proper grounding of electrical systems is crucial for preventing electrical fires. By providing a path for electric current to follow in the event of a fault, grounding reduces the risk of electrical shock and fire.
• Overcurrent Protection (Article 240): Overcurrent protection devices, such as circuit breakers and fuses, are designed to cut off electrical power when the current exceeds a certain level. This prevents overheating of wires and potential electrical fires.
• Wiring Methods and Materials (Articles 300-399): These articles provide guidelines for the proper installation of wiring and related equipment to ensure safety and prevent electrical fires. This includes specifications for conductors, cables, raceways, and boxes, among other components.

Understanding and applying these codes is crucial in minimizing fire risks and ensuring optimal safety in all types of buildings and facilities.

How to Stay Up to Date with NFPA 70 / NEC

Given the rapid evolution of electrical technology, it's important to stay updated with the latest NEC revisions. The NFPA offers numerous resources for ongoing education, including online training, webinars, and certifications.

Regularly reviewing and understanding changes in the NEC can enhance your ability to install, maintain, and use fire safety systems in compliance with the highest safety standards.

Conclusion:

Ground is a source for unwanted currents and also as a return path for main current. While earthing is done not for return path but only for protection of delicate equipment’s. It is an alternate low resistance path for current. Earth is used for the safety of the human body in fault conditions while Grounding (As neutral earth) is used for the protection of equipment’s.